1. Field of the Invention
This invention relates generally to improvements to fuel pressure regulators for fuel injection engines, and more particularly to an apparatus which is installed on a conventional fuel pressure regulator and allows the fuel-to-air ratio to be manually adjusted.
2. Brief Description of the Prior Art
Fuel injection engines are provided with a fuel pressure regulator which is attached to the fuel supply manifold assembly downstream of the fuel injectors and regulates the fuel pressure supplied to the fuel injectors The pressure regulator is a diaphragm operated relief valve in which one side of the diaphragm senses fuel pressure and the other side is subjected to intake manifold vacuum. The nominal fuel pressure is established by a spring pre-load applied to the diaphragm. Balancing one side of the diaphragm with manifold pressure maintains a constant fuel pressure drop across the injectors. Fuel in excess of that used by the engine, is bypassed through the regulator and returns to the fuel tank.
The conventional fuel pressure regulator R is pre-set for nominal fuel pressure at the factory by installing a spring of predetermined strength. The regulator comes from the factory as a sealed unit, and no adjustments can be made on the unit to change the limited range of the fuel-to-air ratio set by the factory.
To obtain high performance, and increased horsepower, it would be desirable to alter or fine tune the factory setting of the fuel-to-air ratio.
There are several patents which disclose various regulating devices for engines.
Stokes, U.S. Pat. No. 2,374,844 discloses a regulating device for controlling the supply of fuel to internal combustion engines whereby fuel is metered through a valve in the shape of a hollow cylinder containing a roughly triangular port.
Wirth et al, U.S. Pat. No. 2,482,956 discloses a fuel supply system for varying the pressure of the fuel in the fuel line which utilizes a device for giving temporary enrichment to the fuel mixture when the throttle valve is opened, and a mechanism having a temperature responsive element for enriching the fuel-to-air mixture while the engine is cold.
Casey et al, U.S. Pat. No. 4,204,507 discloses a fuel injection valve wherein the control of fuel from the fuel bowl to the throat of the throttle body is controlled by a single fuel injector per throat, the fuel injected is pulsed in accordance with a preselected timing scheme by means of an electronic control unit.
The present invention is distinguished over the prior art in general, and these patents in particular by a manually adjustable override apparatus which is connected to an existing fuel pressure regulator to alter the fuel-to-air mixture fed to fuel injectors. A T-shaped member has a lower end adapted to be connected on the vacuum hose fitting of the regulator and has an outwardly extending hose fitting. A headed plunger slidably contained in the longitudinal bore of the T-shaped member has an elongate lower end extending outwardly from the bottom of the T-shaped member and through the hose fitting of the regulator to engage the top of the diaphragm in the regulator. Vacuum communicates around the plunger between the interior of the T-shaped member and the vacuum chamber of the regulator. An adjustment screw in the top end of the T-shaped member engages a small piston slidably and sealably contained in the longitudinal bore. A compression spring is biased between the piston and the head of the plunger.
The existing vacuum hose is removed from the regulator and the override device is installed on the existing regulator. The vacuum hose is re-installed on the hose fitting of the override device. When the adjustment screw is backed off, the diaphragm operates under pressure of the existing factory installed spring in the conventional manner, and when the adjustment screw is screwed in, the plunger is resiliently pressed against the diaphragm under the increased spring pressure of the secondary override spring to increase the pressure on the diaphragm and vary the fuel pressure resulting in a variable fuel-to-air ratio.